1. Field of the Invention
The present invention relates to a process for fabricating an electrode for an oxygen sensor.
2. Description of the Related Art
A proposed process for fabricating of an electrode for an oxygen sensor involves mixing stabilized zirconia powders and platinum powders each having a size of 1 .mu.m or less to obtain a paste of a Pt/ZrO.sub.2 mixture and baking the same onto stabilized zirconia (Japanese Unexamined Patent Publication (Kokai) No. 57-165758). Compared with a platinum electrode, it is expected that this electrode will have improved adhesion to a solid electrolyte since it contains the same element that is contained in the solid electrolyte, such electrodes will have a higher porosity, an increased specific surface area of platinum, and a three phase interface, thereby permitting the operation of the solid electrolyte at a low temperature.
Nevertheless, since the above process uses a mixture of powders, the fineness and dispersibility of the powders are not high and the possible electrode activity is limited. Further, conventional pastes generally require an inorganic additive such as glass frit, which causes the electrode to coagulate and thus deteriorates the electrode.
The object of the present invention is, therefore, to solve the above problem and to provide a process for fabricating an electrode with activity at a lower temperature and with excellent stability.